//哈希
https://leetcode.cn/problems/check-permutation-lcci/
class Solution {
public:
    bool CheckPermutation(string s1, string s2) {
        if(s1.size()!=s2.size())
            return false;

        int hash[26]={0};
        for(auto ch:s1)
            hash[ch-'a']++;
        for(auto ch:s2)
            hash[ch-'a']--;
        for(int i=0;i<26;i++)
            if(hash[i]!=0)
                return false;

        return true;
    }
};